So what's it all about? Here's the back cover text, to let you in — just a little! — on the unfolding story:

Malian of Night and Kalan, her trusted ally, are returning to the Wall of Night—but already it may be too late. The Wall is dangerously weakened, the Nine Houses of the Derai fractured by rivalry and hate. And now, the Darkswarm is rising . . ..

Among Grayharbor backstreets, an orphan boy falls foul of dark forces. On the Wall, a Daughter of Blood must be married off to the Earl of Night, a pawn in the web of her family’s ambition. On the Field of Blood, Kalan fights for a place in the bride’s honor guard, while Malian dodges deadly pursuers in a hunt against time for the fabled Shield of Heaven. But the Darkswarm is gaining strength, and time is running out—for Malian, for Kalan, and for all of Haarth. .